#!/bin/bash
#
# This script is designed to be run inside the container
#

# fail hard and fast even on pipelines
set -eo pipefail

if [[ -f /etc/environment_proxy ]]; then
	source /etc/environment_proxy
fi

# set debug based on envvar
[[ $DEBUG ]] && set -x

# configure etcd
export ETCD_PORT=${ETCD_PORT:-4001}
export ETCD="$HOST:$ETCD_PORT"
export ETCD_PATH=${ETCD_PATH:-/deis/builder}
export ETCD_TTL=${ETCD_TTL:-20}

# wait for etcd to be available
until etcdctl --no-sync -C $ETCD ls >/dev/null 2>&1; do
	echo "waiting for etcd at $ETCD..."
	sleep $(($ETCD_TTL/2))  # sleep for half the TTL
done

# wait until etcd has discarded potentially stale values
sleep $(($ETCD_TTL+1))

function etcd_safe_mkdir {
	set +e
	ERROR="$(etcdctl --no-sync -C $ETCD mkdir $1 2>&1 >/dev/null)"
	if [[ $? -ne 0 && $(echo $ERROR | grep -ive "key already exists") ]]; then
		echo "etcd_safe_mkdir: an etcd error occurred ($ERROR)"
		echo "aborting..."
		exit 1
	fi
	set -e
}

function etcd_set_default_stdin {
	set +e
	ERROR=$(etcdctl --no-sync -C $ETCD mk $ETCD_PATH/$1 2>&1 >/dev/null)
	if [[ $? -ne 0 && $(echo $ERROR | grep -ive "key already exists") ]]; then
		echo "etcd_set_default_stdin: an etcd error occurred ($ERROR)"
        echo "aborting..."
		exit 1
	fi
	set -e
}

function etcd_get {
	etcdctl --no-sync -C $ETCD get $ETCD_PATH/$1
}

etcd_safe_mkdir $ETCD_PATH/users

# wait for confd to run once and install initial templates
until confd -onetime -node $ETCD --log-level error; do
	echo "builder: waiting for confd to write initial templates..."
	sleep $(($ETCD_TTL/2))  # sleep for half the TTL
done

# spawn confd in the background to update services based on etcd changes
confd -node $ETCD --log-level error --interval 5 &
CONFD_PID=$!

# remove any pre-existing docker.sock
test -e /var/run/docker.sock && rm -f /var/run/docker.sock

# force overlayfs if the Docker daemon on the host is using it
mkdir --parents --mode=0700 /
fstype=$(findmnt --noheadings --output FSTYPE --target /)
if [[ "$fstype" == "overlay" ]]; then
	DRIVER_OVERRIDE="--storage-driver=overlay"
fi

# spawn a docker daemon to run builds
docker -d --bip=172.19.42.1/16 $DRIVER_OVERRIDE --insecure-registry 10.0.0.0/8 --insecure-registry 172.16.0.0/12 --insecure-registry 192.168.0.0/16 --insecure-registry 100.64.0.0/10 &
DOCKER_PID=$!

# wait for docker to start
while [[ ! -e /var/run/docker.sock ]]; do
	sleep 1
done

# build required images
docker build -t deis/slugbuilder /usr/local/src/slugbuilder/
docker build -t deis/slugrunner /usr/local/src/slugrunner/

function gen_host_keys {
	if ! etcd_get sshHostKey; then
		# generate the keys, then set them up in etcd
		/usr/bin/ssh-keygen -A
		for type in dsa ecdsa ed25519 rsa; do
			cat "/etc/ssh/ssh_host_${type}_key" | etcd_set_default_stdin "sshHost${type}Key"
			cat "/etc/ssh/ssh_host_${type}_key.pub" | etcd_set_default_stdin "sshHost${type}PubKey"
		done
		cat "etc/ssh/ssh_host_key" | etcd_set_default_stdin sshHostKey
		cat "/etc/ssh/ssh_host_key.pub" | etcd_set_default_stdin sshHostPubKey
	else
		# pull the keys from etcd
		for type in dsa ecdsa ed25519 rsa; do
			etcd_get "sshHost${type}Key" > "/etc/ssh/ssh_host_${type}_key"
			etcd_get "sshHost${type}PubKey" > "/etc/ssh/ssh_host_${type}_key.pub"
		done
		etcd_get sshHostKey > /etc/ssh/ssh_host_key
		etcd_get sshHostPubKey > /etc/ssh/ssh_host_key.pub
	fi
}

gen_host_keys

# start an SSH daemon to process `git push` requests
/usr/sbin/sshd -D -e &
SSHD_PID=$!

# start a cleanup script to remote old repositories and images
/bin/cleanup &
CLEANUP_PID=$!

# smart shutdown on SIGINT and SIGTERM
function on_exit() {
	kill -TERM $DOCKER_PID $SSHD_PID $CLEANUP_PID
	wait $DOCKER_PID $SSHD_PID $CLEANUP_PID 2>/dev/null
	exit 0
}
trap on_exit INT TERM EXIT

echo deis-builder running...

# publish the service to etcd using the injected EXTERNAL_PORT
if [[ ! -z $EXTERNAL_PORT ]]; then

	# configure service discovery
	PORT=${PORT:-22}
	PROTO=${PROTO:-tcp}

	set +e

	# wait for the service to become available on PORT
	sleep 1 && while [[ -z $(netstat -lnt | awk "\$6 == \"LISTEN\" && \$4 ~ \".$PORT\" && \$1 ~ \"$PROTO.?\"") ]] ; do sleep 1; done

	# while the port is listening, publish to etcd
	while [[ ! -z $(netstat -lnt | awk "\$6 == \"LISTEN\" && \$4 ~ \".$PORT\" && \$1 ~ \"$PROTO.?\"") ]] ; do
		etcdctl --no-sync -C $ETCD set $ETCD_PATH/host $HOST --ttl $ETCD_TTL >/dev/null
		etcdctl --no-sync -C $ETCD set $ETCD_PATH/port $EXTERNAL_PORT --ttl $ETCD_TTL >/dev/null
		sleep $(($ETCD_TTL/2)) # sleep for half the TTL
	done

	# if the loop quits, something went wrong
	exit 1

fi

wait